Strand annealing apparatus



A- N. GRAY STRAND ANNEALING APPARATUS Sept 10, 1957 Fild Nov. s, 1955 2 Sheets-Sheet 1 J\Nk I 7/ /////z J on.

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Se t 10, 1957 A. N. GRAY STRAND ANNEALING APPARATUS 2 Sheets-Sheet 2 Filed Nov. 3, 1955 United States Patent STRAND ANN EALING APPARATUS Alvin N. Gray, Edgewood, Md, assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application November 3, 1955, Serial No. 544,77 7

14 Claims. (Cl. 219-155) This invention relates to strand annealing apparatus, and more particularly to apparatus for continuously annealing strands of indefinite length.

Many types of apparatus have been devised for heating conductive strands to annealing temperatures. Heretofore, in the treatment of such strands, it has been a common practice to advance the strands around conductive sheaves and to apply a difference in electrical potential between at least two of such sheaves. This potential difierence causes a current to flow through the length of a strand advancing between the sheaves, and thereby heat and anneal the strand therebetween. The desired temperature for the annealing is obtained by varying the potential difference between the sheaves and the speed of travel of the strand.

Employing an annealing apparatus that includes sheaves has certain disadvantages. Usually the sheaves are sup ported by ball bearings, the initial cost and maintenance of which are high. Brushes and slip rings must be provided for applying Voltages to the sheaves. Also, since the sheaves and their supporting structure are heated during the annealing operation of the strands, expensive lubricants that can withstand such heat must be provided for the bearings.

It is an object of this invention to provide new and improved strand annealing apparatus.

It is a further object of this invention to provide new and improved apparatus for continuously annealing strands of indefinite length.

Other objects of this invention will become apparent as the specification proceeds.

Strand annealing apparatus embodying certain features of this invention may include a plurality of massive blocks of conductive material, means for advancing the strand continuously over substantially the entire length of each of the blocks and means for applying a voltage between the blocks.

More specifically, apparatus for continuously annealing strands of indefinite length, embodying certain features of the invention, may include three large copper blocks, each of which has a surface that is curved in the same direction as the path of the stran The blocks are aligned in a vertical plane and are staggered horizontally with the center block at a level higher than the level of the two outside blocks. The curved surfaces of the outside blocks face downwardly and that of the center block faces upwardly so that the strand to be annealed is passed below the outside blocks, and above the center block. A capstan advances the strand continuously over the curved surfaces of the blocks and sufiicient tension is maintained on the strand to hold the strand in intimate contact with substantially the entire lengths of such surfaces. A potential difierence is applied between the center block and each of the outside blocks so that the strand passing therebetween is heated and annealed.

A complete understanding of the invention may be had from the following detailed description of specific embodiments thereof, when read in conjunction with the appended drawings, in which:

Fig. l is a side elevation of apparatus for annealing an electrically-conductive strand and covering the strand Patented Sept. 10, 1957 with insulating material, and shows schematically an electric circuit used in conjunction therewith;

Fig. 2 is a side elevation of a portion of the apparatus shown in Fig. 1, showing annealing apparatus forming a specific embodiment of the invention;

Fig. 3 is an enlarged, vertical section taken along line 3-3 of Fig. 2;

Fig. 4 is an enlarged, vertical section taken along line 4-4 of Fig. 2;

Fig. 5 is a plan view of an alternate embodiment of the invention;

Fig. 6 is an enlarged, vertical section taken along line 6-6 of Fig. 5, and

Fig. 7 is an enlarged, vertical section taken along line 7-7 of Fig. 5.

Referring to Fig. 1, an annealing apparatus 10 is shown for annealing an electrically-conductive strand 11, such as a copper wire, immediately prior to covering the strand with an insulating material. The strand 11 is withdrawn from a supply reel 12, annealed in the annealing apparatus 10 and then enclosed in a covering of insulating material by an extruder 15. The strand 11 is advanced through the various operations by a driven capstan 16 and the annealed, insulated conductor is wound onto a driven takeup real 17.

The strand 11 is annealed by passing an electric current through predetermined lengths thereof. The current is derived from a source 20 of variable voltage through a plurality of conductors 21, 22 and 23. The voltage source 20 may include transformers and other apparatus (not shown) for deriving a current suitable for annealing the strand 11.

Referring to Figs. 2 to 4, inclusive, the annealing apparatus 10 is shown in greater detail. The strand 11 is passed over a sheave 24 and through a plurality of electrodes 25, 26 and 27, which are energized by the voltage source 20. It is between these electrodes that the strand 11 is annealed as it is advanced continuously by the capstan 16. The outside electrodes 25 and 27 are similar in construction and are connected .to the grounded side of the voltage source 20 through the conductors 21 and 23, respectively. The side of the source 20 having a suitable voltage thereon is connected to the center electrode 26 through the conductor 22.

The electrodes 25, 26 and 27 are mounted on a channel 30, which is secured to a platform 31 of suitable height. The electrode 26 includes a massive copper block 32 secured by screws 34-34 to a block 35 of insulating material. The block 35 is fixed to the channel 30 by a plurality of side plates 36-36 (Figs. 2 and 4). A groove 37 is formed in the upper surface of the block 32, and the groove is curved in the same direction as that of the path of the strand 11, as shown in Fig. 2. The conductor 22 is secured to the center block 32 through a lug 40 secured to the end of the conductor 22.

Since the electrodes 25 and 27 are constructed simiiarly, a description of the construction of the electrode 25 will suffi'ce for both. Referring to Figs. 2 and 3, the electrode 25 includes a C-shaped, conductive member 41 which is welded to a spacer 58 which is welded to the channel 30. A backing plate 42 is secured adjustably to the upper side of the C-shaped member 41 by a bolt 45. The plate 42 can be set at various levels by rotating the bolt 45, which is threaded within a nut 46 welded to the upper side of the member 41. The lower end of the bolt 45 is unthreaded and is journaled rotatably within the plate 42. A lock nut 47 is provided for securing the plate 42 fixedly, after the plate has been adjusted to a predetermined position by rotating the bolt 45.

Guide rods 50-50, secured to the plate 42, are mounted slidably within sleeves 51-51 welded to the upper side of the C-shaped member 41 to prevent the plate 42 from pivoting around the bolt 45 when the bolt is rotated: A massive copper block 52 is secured to the plate 42 by screws 55-55. A groove 56 is formed in the block 52 to guide the strand 11, and the groove is curved in the same direction as the path of the strand 11, as shown in Fig. 2. The grounded conductor 21 is secured to the C-shaped member 41 through a lug 57 so that the copper block 52 is at ground potential.

As stated hereinabove, the electrode 27 isconstructed almost like the electrode 25. The only difference between the two electrodes resides in the manner in which they are secured in the path of the strand 11. The electrode 25 is welded to the spacer 58 while the electrode 27 is mounted securely within a trough 60. The trough 60 is secured within a discharge trough 61 fired by suitable means (not shown) to the channel 30. Like the electrode 25, the electrode 27 includes a massive copper block 62, the height of which may be adjusted by rotating a bolt 63 and fixed by a lock nut 65. The block 62 also has a groove 66 formed in the lower side thereof, with the groove 66 curved in a direction conforming to the path of the strand 11.

e In order to limit oxidation of the conductive strand 11 during the annealing thereof, the trough 60 is filled with boiling water conveyed to the trough 60 through a supply pipe 67. The strand 11 enters the trough 60 through a slot 71 formed within one end of the trough, and leaves through a slot 71 formed Within the opposite end of the trough. The water supplied to the trough 6t) overflows through the slots 70 and 71 continuously and flows into the discharge trough 61. The water is then directed into a discharge pipe 72 and is carried to suitable means (not shown) for heating the water to boiling temperature and for recirculating the water to the supply pipe 67.

The strand 11 passes from the electrode 27 to a compressed-air wiper 75. Air under pressure is supplied to the wiper 75 through a tube 76 and is directed at various angles against the surface of the strand 11 to force any Water from the surface that may adhere thereto after the strand leaves the water within the trough 66. Since such Wipers are well known in the art, a more detailed description will not be necessary. The wiper 75 is tilted so that any water removed from the strand 11 flows into the discharge trough 61. From the wiper 75, the strand 11 passes over a sheave 77 which directs the strand to the extruder 15.

OPERATION When the strand 11 is to be annealed and covered with an insulating material by the apparatus shown in Figs. 1 to 4, inclusive, the strand is withdrawn from the supply reel 12, passed over the sheave 24 and directed within the groove 56 of the copper block 52. The strand 11 is then advanced over the copper block 32, along the groove 37 thereof, and is immersed beneath the level of the water within the trough 61 by advancing it along the groove 66 of the copper block 62. The strand 11 is then threaded through the air wiper 75 and is directed to the extruder by the sheave 77. From the extruder 15, the strand 11 is wound around the capstan 16 andthe end thereof is connected to the takeup reel 17. The extruder 15, the capstan 16 and the takeup reel 17 are energized to advance the strand 11 through the annealing and extruding operations. Compressed air is then supplied to the Wiper 75 through the tube 76 and the voltage source is energized.

When the voltage source 21 is energized, voltages are applied between the first block 52 in the series and the center block 32, and between the center block 32 and the last block 62 in the series. The voltage that is applied across the first block 52 and the center block 32 Will cause a current to pass through the section of the strand 11 located between these blocks, The current will beat this section of the strand to progressively higher temperatures from the first block 52 to the center block 32. The voltage source 2 3 is varied so that the temperature of a portion of the strand near the center block 32 is equal to the annealing temperature of the strand. The voltage that is applied between the center block 32 and the end block 62 will cause further annealing of the strand 11 between the blocks 32 and 6 2.

By immersing the strand 11 beneath the water within the trough 6%, oxidation of the strand 11 is limited, if not entirely prevented. The water within the trough is main tained at boiling temperatures so that the various tem peratures along the length of the strand 11 will be constant as the strand is advanced through the annealing apparatus. These temperatures would vary if the water within the trough were at room temperature at the beginning of the annealing operation.

Since the voltage applied across the sections of the strand 11 between the electrodes 25, 26 and 27 will heat the Wire to predetermined temperatures (in the order of! from about 800 F. to about 900 F. for a copper strand 11), the heated strand 11 would increase the temperature of the water slowly if it were at room temperature originally. Since the temperature of the boiling water Within the trough will remain substantially constant, better control of the temperature of the strand 11 as it leaves the annealing apparatus 10 is obtained. To have such control is important, since it is preferable that the strand 11 be at an elevated temperature as it passes through the eXtruder 15 and has a covering of insulating material applied therearound.

As [the capstan 16 withdraws the strand 11 from the supply reel 12 and advances the strand through the annealing apparatus 10 and the extruder 15, tension will be developed on the strand. The tension developed between the extruder 15 and the supply reel 12 must be sufiicient to force the strand intimately against the copper blocks 52, 32 and 62 as the strand passes in its tortuous path through the annealing apparatus 19. To vary this tension and, hence, to insure that the strand 11 contacts intimately the full length of the grooves 56, 37 and 66 in the blocks 52, 32 and 62, respectively, the positions of the blocks 52 and 62 are adjusted by loosening the lock nuts 47 and and rotating the bolts 4-5 and 63 as hereinbefore described.

By so adjusting the positions of the blocks 52 and 62 so that the strand 11 contacts the entire lengths of the grooves therein, more efficient electrical contact is made because the current density of the portions of the strand 11 in actual contact with the blocks will be constant. If

'the grooves 56, 37 and 66 were not curved, the current densities at the ends of the blocks 52, 32 and 62 would be greater than that the centers thereof.

Alternate embodiment In the embodiment of the invention shown in Figs. 1 to 4, inclusive, each of the copper blocks 52, 32 and 62 has a groove in the surface that contacts the strand 11. While such grooves aid in directing the strand 11 along its path through the annealing apparatus 11 the grooves will become worn by the strand 11 passing continually Itherethrough so that eventually it will be necessary to replace blocks 52, 32 and 62. In the embodiment of the invention shown in Figs. 5 to 7, inclusive, an annealing apparatus 119 is shown wherein this disadvantage is alleviated to a great extent.

Referring to Figs. 5 to 7, inclusive, a conductive strand 111 to be annealed is directed through electrodes 125, 126 and 127 which function similarly to the electrodes 25, 26 and 27, respectively. The electrodes 125, and 127, however, have no blocks having grooves in the contacting surfaces thereof like the blocks 52, 32 and 62 of Fig. 2. Sheaves 124 and 177 are secured to a platform 131 on both sides of the annealing apparatus 119 for directing the strand 111 therethrough.

Each of the outside electrodes 125 and 127 is con structed similarly, and such construction will be described with reference to the electrode 125 shown in Figs. 5 and 6. The electrode 125 includes a copper block 152 which has no grooves in the contacting surface thereof, but which has provided a pair of flanges 180-180 integral with the block 152. Similarly, the center electrode 126 shown in Fig. 7 includes a copper block 132 having flanges 181-181 on both sides of the contacting surface thereof. The end electrode 127 includes a block 162, which is constructed similarly to the block 152 and has integral flanges similar to the flanges 180-180 thereon. The center block 132 is energized by a suitable source of annealing voltage (not shown) through a conductor 122 and the outside blocks 152 and 162 are connected to the grounded side of the voltage source through the conductors 121 and 123, respectively.

While the sheaves 12d and 177 will direct the strand 111 over the surfaces of the blocks 152, 132 and 162 in a straight path under normal conditions, the flanges 180-182 and 181-181 are provided in case some abnormal condition should tcnd to force the strand 111 from its path and off of the blocks. All of the contacting surfaces of the blocks 152, 132 and 162 are curved in a direction parallel to that of the strand 111 passing thereover. In this respect, the strips on the surfaces of the blocks 152, 132 and 162 that actually contact the strand 111 are similar to the grooved surfaces of the blocks 52, 32 and 62 which contact the strand 11 in the embodiment shown in Figs. 1 to 4, inclusive. Further, the level of the blocks 152 and 162 is adjustable by rotating bolts 1 55 and 163, respectively, as described for the electrode 25 shown in Fig. 3.

During the annealing of the strand 111 by the apparatus shown in Figs. 5, 6 and 7, the contacting surfaces of the blocks 152, 132 and 162 will eventually become worn. When this occurs, the blocks are shifted laterally. In order to shift the position of the blocks 152, 132 and 162 laterally with respect to the path of the strand 111, the electrodes 125 to 127, inclusive, are secured to a movable channel 131 A C-shaped member 141 of the electrode 125 is welded to a spacer 158 which is welded to the channel 130, and the electrode 127 is secured in a similar manner. The copper block 132 of the electrode 126 is fixed to a block 135 of insulating material secured to the channel 131) by side plates 136-136.

A cylindrical sleeve 182 is pressed in place between two legs 185-185 of the channel 130 near both ends thereof. Each sleeve 182 is in alignment with apertures 186-186 formed within the legs 185-185, and each is mounted slidably on a guide rod 187. The guide rods 1871$7 are secured fixedly to a platform 1.31 by brackets 190-191 The channel 130 can, therefore, be moved laterally with respect to the advancing strand 111. To so move the channel 134 accurately, an internally threaded sleeve 191 is pressed in place between the legs 185-185 of the channel 130 at the center thereof. A threaded shaft 192 is journaled rotatably within bearings 195-195, and the thread thereof cooperates with the internal thread of the sleeve 191. A handwheel 196 is secured fixedly to one end of the threaded shaft 192 and rotation thereof will move the blocks 152, 132 and 162 laterally with respect to the continuously advancing strand 111.

Operation of alternate embodiment When the strand 111 is to be annealed by the annealing apparatus 110 of Figs. 5 to 7, inclusive, the strand is passed successively over the curved contacting surfaces of the bioclrs 152, 132 and 162. The levels of the outside blocks 152 and 162 are varied by rotating the bolts 145 and so that the strand 111 will contact the entire lengths of the curved surfaces on the blocks 152, 132 and 162, and the correct tension will be developed in the strand. The annealing of the strand 111 is etfected 6 by applying an annealing voltage between the blocks 152 and 132 and between the blocks 132 and 162 through the conductors 121, 122 and 123.

As the strand 111 is annealed continuously, the strand will wear grooves in the contacting surfaces of the copper blocks 152, 132 and 162. When such grooves are worn to a predetermined depth within the contacting surfaces, the handwheel 196 is rotated to move the channel and, hence, the blocks 152, 132 and 162 laterally of the path of the strand 111 so that unworn areas of the surfaces on the blocks contact the strand. After a second groove is formed in the contacting surfaces, the blocks 152, 132 and 162 are again moved laterally. This progressive movement of the copper blocks is continued until grooves are worn over substantially the complete contacting surfaces thereof. At this time, it will be necessary to replace the copper blocks 152, 132 and 162 with new contact blocks.

Means for preventing oxidation of the strand 111 may be provided for the embodiment shown in Figs. 5 to 7, inclusive. Such means may include a trough filled with boiling water into which the wire is immersed, as shown in 'Fig. 2, or some other suitable oxidation-preventing means. For example, the strand 111 may be surrounded by a tube to which steam is provided so that air is excluded from the strand during the annealing thereof. The water filled trough is preferred, however, because of its simplicity and because the temperature of the strand as it passes to the extruder can be controlled readily, as described hereinbefore. Since the electrode that is positioned Within the water is at ground potential, there is no danger to personnel operating the annealing apparatus.

While the above-described annealing apparatus shows three electrodes, it is to be understood that any other suitable number of electrodes may be used without departing from the spirit and scope of the invention.

What is claimed is:

1. Strand annealing apparatus which comprises a plurality of massive blocks of conductive material, means for advancing the strand continuously over substantially the entire length of each of the blocks, and means for applying a voltage between the blocks.

2. Apparatus for continuously annealing a strand of indefinite length, which comprises a plurality of massive blocks of conductive material aligned in tandem, means for advancing the strand over a surface of each block and maintaining the strand in intimate contact with the surfaces over the entire lengths of the blocks, and means for applying a voltage between the blocks to anneal the strand therebetween.

3. Apparatus for continuously annealing a strand of indefinite length, which comprises a plurality of massive blocks of conductive material aligned in tandem, means for advancing the strand over a surface of each block, means for varying the positions of the blocks toward and away from the path of the strand to vary the tension on the strand and to maintain the strand in intimate contact with the surfaces over the entire lengths of the blocks, and means for applying a voltage between the blocks to anneal the strand therebetween.

4. Apparatus for annealing a conductive strand of indefinite length, which comprises a plurality of massive blocks of conductive material, means for advancing the strand over a surface of each block and in intimate contact with substantially the entire length of such surface, the contacting surface of each block being curved in a direction parallel to the path of the strand advancing thereover so that the current density of the sections of the strand in contact with the curved surfaces is substantially constant, and means for applying a voltage between adjacent blocks to anneal the strand passing therebetween.

5. Apparatus for annealing conductive strands, which comprises a plurality of massive blocks of conductive material aligned in tandem, means for advancing a strand over a surface on each of the blocks and maintaining the 7 strand in intimate contact with such surfaces over the entire lengths of the blocks, means for applying a voltage between the blocks to anneal the strand as it passes therebetween, and means for preventing oxidation of the strand during the annealing thereof.

6. Apparatus for continuously annealing a conductive strand of indefinite length, which comprises a series of massive blocks of conductive material aligned in tandem, means for advancing the strand over the surfaces of the blocks and for maintaining the strand in intimate contact with such surfaces over the entire lengths of the blocks, a trough containing a body of water in which the last block in the series is immersed so that the strand is passed therethrough and oxidation of the strand is limited, and means for applying voltages between adjacent blocks in the series for annealing the strand 'between such adjacent blocks.

7. Apparatus for annealing strands, which comprises a series of blocks of conductive material aligned in tandem, successive blocks in the series being positioned alternately on different horizontal levels, means for continuously advancing a strand alternately over one block and under the adjacent block in the series, and means for applying a potential difference between adjacent blocks.

8. Apparatus for annealing a conductive strand, which compriss a plurality of massive blocks of conductive material, the blocks being aligned in a vertical direction and adjacent blocks being positioned alternately above and below a predetermined horizontal plane, each of the blocks having a surface thereon that is curved in a direction away from the horizontal plane, means for advancing the strand over the curved surfaces and for maintaining suflicient tension thereon to cause the strand to contact the entire lengths of the surfaces, and means for applying a voltage between adjacent blocks to anneal the strand as it passes therebetween.

9. Apparatus for annealing a conductive strand, which comprises three massive blocks of conductive material aligned in tandem, means for advancing the strand continuously over a surface of each block and in contact with such surfaces, the contacting surfaces being curved in a direction parallel to the path of the advancing strand with the curved surfaces of the two outside blocks facing in a direction opposite to that in which the curved surface of the inside block faces, means for varying the position of the outside blocks toward and away from the path of the advancing strand for maintaining sufficient tension on the strand to cause it to contact the entire lengths of the contacting surfaces, and means for applying voltages between the center block and the outside blocks to anneal the strand as it passes between the blocks.

10. Apparatus for annealing a conductive strand, which comprises a base, a first copper block secured fixedly to and insulated electrically from the base, second and third copper blocks secured adjustably to the base, each of the blocks having a groove formed in one surface thereof, the first block being located between the second and third blocks so that the grooves therein are in alignment in a vertical plane and staggered horizontally with the groove in the first block on a level higher than the level on which are the grooves in the second and third blocks, the grooved surface of the first block facing upwardly and the grooved surfaces of the second and third blocks facing downwardly so that the strand to be annealed may be passed over the first block and under the second and third blocks, the grooves being curved longitudinally of the path of the strand to be annealed so that the strand contacts the entire lengths of the grooves intimately, a source of voltage connected between the first block and the second and third blocks for causing a flow of current through the sections of the strand between the blocks to heat and anneal such sections, sheaves secured to the base at a level higher than the grooves in the second and third blocks for directing the strand to the groove in the a second block and from the groove in the third block, ad usting means associated with the second and third t? blocks for varying the vertical levels of such blocks whereby the tension on the strand is varied, and a capstan for advancing the strand continuously through the grooves in the blocks. 7

11. Apparatus for annealing a conductive strand, which comprises a plurality of massive blocks of conductive material aligned in tandem, means for advancing the strand over a surface of each block and in intimate contact with the entire lengths of such surfaces, means for adjusting the positions of the blocks in a direction lateral to that of the advancing strand, and means for applying a voltage across adjacent blocks for annealing the strand therebetween.

12. Apparatus for annealing a conductive strand of indefinite length, which comprises a plurality of massive blocks of conductive material in a series, the blocks being aligned with respect to a vertical plane and staggered with respect to a horizontal plane, means for advancing the strand continuously over a surface of each block with the horizontal staggering thereof causing the strand to take a zigzag path over such surfaces, means for varying the positions of alternate blocks vertically to vary the tension on the strand and to cause the strand to contact the entire lengths of the block surfaces, means for adjusting the positions of the blocks simultaneously in a horizontal direction, and means for applying a voltage between adjacent blocks in the series for annealing the strand as it passes therebetween.

13. Apparatus for annealing a conductive strand, which comprises a base, a plurality of massive blocks of conductive material secured to the base and aligned in a series with adjacent blocks being insulated from each other, each of the blocks having a curved surface thereon with such surfaces of adjacent blocks in the series facing in opposite directions, means for advancing the strand continuously over the curved surfaces and maintaining sufficient tension thereon so that the strand contacts substantially the entire length of such surfaces, means for shifting the base laterally of the advancing strand so that the strand contacts difierent areas of the surfaces of the blocks as areas being contacted by the strand become worn, and means for applying a potential difference between adjacent blocks in the series for annealing the strand as it passes therebetween.

14. Apparatus for annealing a conductive strand, which comprises a base, a first massive copper block secured to and insulated from the base, second and third massive copper blocks mounted on the base with one of such blocks on each side of the first block, means for varying the ositions of the second and third blocks toward and away from the base, each of the three blocks having a curved surface in one face thereof with the curved sur face of the first block facing in a direction opposite to that in which the surfaces of the second and third blocks face, a capstan for advancing the strand continuously in a zigzag path over the curved surfaces of the blocks and maintaining sufficient tension on the strand so that the strand contacts the surfaces intimately over the entire lengths thereof, means for moving the base progressively in a direction laterally of the path of the advancing strand so that the strand contacts difierent areas on the surfaces of the blocks, and a voltage source connected electrically between the first and the second blocks and the first and third blocks for causing a sufficient annealing current to flow through the strand between such blocks.

Referenees flit-ed in the file of this patent UNITED STATES PATENTS 1,886,631 Bradley Nov. 8, 1932 2,176,583 Cook Oct. 17, 1939 2,421,537 Bayers June 3, 1947 FOREIGN PATENTS 87,118 Austria J an. 25, 1922 

